_PAD = b"_PAD"
_GO = b"_GO"
_EOS = b"_EOS"
_UNK = b"_UNK"

_START_VOCAB = [_PAD, _GO, _EOS, _UNK]

PAD_ID = 0
GO_ID = 1
EOS_ID = 2
UNK_ID = 3
